191 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * si7005.c - Support for Silabs Si7005 humidity and temperature sensor4 *5 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>6 *7 * (7-bit I2C slave address 0x40)8 *9 * TODO: heater, fast mode, processed mode (temp. / linearity compensation)10 */11 12#include <linux/err.h>13#include <linux/i2c.h>14#include <linux/delay.h>15#include <linux/module.h>16#include <linux/pm.h>17 18#include <linux/iio/iio.h>19#include <linux/iio/sysfs.h>20 21#define SI7005_STATUS 0x0022#define SI7005_DATA 0x01 /* 16-bit, MSB */23#define SI7005_CONFIG 0x0324#define SI7005_ID 0x1125 26#define SI7005_STATUS_NRDY BIT(0)27#define SI7005_CONFIG_TEMP BIT(4)28#define SI7005_CONFIG_START BIT(0)29 30#define SI7005_ID_7005 0x5031#define SI7005_ID_7015 0xf032 33struct si7005_data {34 struct i2c_client *client;35 struct mutex lock;36 u8 config;37};38 39static int si7005_read_measurement(struct si7005_data *data, bool temp)40{41 int tries = 50;42 int ret;43 44 mutex_lock(&data->lock);45 46 ret = i2c_smbus_write_byte_data(data->client, SI7005_CONFIG,47 data->config | SI7005_CONFIG_START |48 (temp ? SI7005_CONFIG_TEMP : 0));49 if (ret < 0)50 goto done;51 52 while (tries-- > 0) {53 msleep(20);54 ret = i2c_smbus_read_byte_data(data->client, SI7005_STATUS);55 if (ret < 0)56 goto done;57 if (!(ret & SI7005_STATUS_NRDY))58 break;59 }60 if (tries < 0) {61 ret = -EIO;62 goto done;63 }64 65 ret = i2c_smbus_read_word_swapped(data->client, SI7005_DATA);66 67done:68 mutex_unlock(&data->lock);69 70 return ret;71}72 73static int si7005_read_raw(struct iio_dev *indio_dev,74 struct iio_chan_spec const *chan, int *val,75 int *val2, long mask)76{77 struct si7005_data *data = iio_priv(indio_dev);78 int ret;79 80 switch (mask) {81 case IIO_CHAN_INFO_RAW:82 ret = si7005_read_measurement(data, chan->type == IIO_TEMP);83 if (ret < 0)84 return ret;85 *val = ret;86 return IIO_VAL_INT;87 case IIO_CHAN_INFO_SCALE:88 if (chan->type == IIO_TEMP) {89 *val = 7;90 *val2 = 812500;91 } else {92 *val = 3;93 *val2 = 906250;94 }95 return IIO_VAL_INT_PLUS_MICRO;96 case IIO_CHAN_INFO_OFFSET:97 if (chan->type == IIO_TEMP)98 *val = -50 * 32 * 4;99 else100 *val = -24 * 16 * 16;101 return IIO_VAL_INT;102 default:103 break;104 }105 106 return -EINVAL;107}108 109static const struct iio_chan_spec si7005_channels[] = {110 {111 .type = IIO_HUMIDITYRELATIVE,112 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |113 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),114 },115 {116 .type = IIO_TEMP,117 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |118 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),119 }120};121 122static const struct iio_info si7005_info = {123 .read_raw = si7005_read_raw,124};125 126static int si7005_probe(struct i2c_client *client)127{128 struct iio_dev *indio_dev;129 struct si7005_data *data;130 int ret;131 132 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))133 return -EOPNOTSUPP;134 135 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));136 if (!indio_dev)137 return -ENOMEM;138 139 data = iio_priv(indio_dev);140 i2c_set_clientdata(client, indio_dev);141 data->client = client;142 mutex_init(&data->lock);143 144 indio_dev->name = dev_name(&client->dev);145 indio_dev->modes = INDIO_DIRECT_MODE;146 indio_dev->info = &si7005_info;147 148 indio_dev->channels = si7005_channels;149 indio_dev->num_channels = ARRAY_SIZE(si7005_channels);150 151 ret = i2c_smbus_read_byte_data(client, SI7005_ID);152 if (ret < 0)153 return ret;154 if (ret != SI7005_ID_7005 && ret != SI7005_ID_7015)155 return -ENODEV;156 157 ret = i2c_smbus_read_byte_data(client, SI7005_CONFIG);158 if (ret < 0)159 return ret;160 data->config = ret;161 162 return devm_iio_device_register(&client->dev, indio_dev);163}164 165static const struct i2c_device_id si7005_id[] = {166 { "si7005" },167 { "th02" },168 { }169};170MODULE_DEVICE_TABLE(i2c, si7005_id);171 172static const struct of_device_id si7005_dt_ids[] = {173 { .compatible = "silabs,si7005" },174 { }175};176MODULE_DEVICE_TABLE(of, si7005_dt_ids);177 178static struct i2c_driver si7005_driver = {179 .driver = {180 .name = "si7005",181 .of_match_table = si7005_dt_ids,182 },183 .probe = si7005_probe,184 .id_table = si7005_id,185};186module_i2c_driver(si7005_driver);187 188MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");189MODULE_DESCRIPTION("Silabs Si7005 humidity and temperature sensor driver");190MODULE_LICENSE("GPL");191